It is known in the prior art to threadedly mount a tubular barrel to a writing cartridge located within the barrel so that relative rotation between the writing cartridge and the barrel results in axial displacement of the barrel relative to the cartridge. In that construction the writing tip may be shrouded by the barrel when the writing instrument is not being used. See, for example, U.S. Pat. Nos. 2,441,280 and 2,603,186 for a description of that type of writing instrument. Similarly, it is known to threadedly attach a short, tubular shroud sleeve to the barrel of a writing instrument for the same purpose.
Although these prior art systems have functioned as intended, they have exhibited several characteristics which leave room for improvement. For example, in some cases the threadedly connected parts have not been sufficiently tight to prevent a noticeable amount of axial play between the two parts. In other designs, the parts were complex and expensive to manufacturer while in other cases they were not conducive to use in attractively styled writing instruments.
It would be desirable, therefore, to provide a novel writing instrument of the heretofor mentioned type wherein the projection/retraction mechanism is durable, yet simple in construction and easy to assemble with automated assembly techniques.